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Biomedical subjects

Nils-Claudius Gellrich

Publications and source records attributed to Nils-Claudius Gellrich.

At least 19 recordsLinked to original sources
PubMed2007

One- or two-stage palate closure in patients with unilateral cleft lip and palate: comparing cephalometric and occlusal outcomes.

OBJECTIVE: To assess facial growth and dentoalveolar development in two groups of patients with complete unilateral cleft lip and palate. Primary surgical treatment differed in the timing of hard palate closure. DESIGN: Forty-three patients with unilateral cleft lip and palate were examined. Twenty-two patients underwent early one-stage closure of the hard and soft palate cleft (mean age 23.0 +/- 4.7 months); in 21 patients, the hard palate closure was delayed to 86.3 +/- 39.2 months of age. Lateral cephalograms and dental casts were consecutively analyzed at four stages between 6 and 18 years of age. RESULTS: Lateral cephalometric analysis revealed no significant intergroup differences in the sagittal and vertical craniofacial dimensions at any time. Dental cast analysis showed constriction of the upper anterior arch width at the ages of 6 and 10 years in patients with one-stage surgical palate closure, but a difference could no longer be verified at the ages of 15 and 18 years. CONCLUSIONS: The transverse distances in the upper jaw developed initially more positively in the group with delayed hard palate closure, but it became apparent later that the transverse deficiency after one-stage palate closure could be compensated for. When considering surgical treatment in general, the advantages of the delayed hard palate closure must be weighed against criteria favoring the early one-stage closure of the hard and soft palate.

Adolescent↗
PubMed2006

Anatomical 3-dimensional pre-bent titanium implant for orbital floor fractures.

PURPOSE: This cadaver study evaluates the use of pre-bent 3-dimensional titanium mesh implants for orbital floor and medial wall reconstruction. DESIGN: Nonrandomized comparative study. PARTICIPANTS: Eight human cadaveric heads (n = 16 orbits). METHODS: Transcutaneous incisions were used to expose both orbital floors in each cadaveric head. Unilateral orbital floor and medial wall fractures were generated in each specimen. The contralateral orbit remained uninjured. The fractures then were repaired with pre-bent titanium mesh fan plates molded from aluminum templates presenting different sizes. The templates were generated from topographical computed tomography (CT) data previously obtained from normal subjects. The accuracy of orbital reconstruction was evaluated with postoperative CT scans. MAIN OUTCOME MEASURES: The mean value of the distances between the implant and the bony orbit was evaluated. RESULTS: The mean distance between all 16 plates and their respective orbital floors/medial walls was 0.81+/-0.74 mm. Mean values were 0.68+/-0.63 mm for the unfractured side and 0.93+/-0.82 mm for the fractured side. No significant differences were found between orbits when evaluated for side of injury, gender, or size of defect. CONCLUSION: Pre-bent 3-dimensional titanium mesh implants provide accurate reconstruction of orbital floor and medial orbital wall fractures. The mean implant error was <1 mm for all orbits studied.

Adult↗
PubMed2006

Angiogenic and inflammatory response to biodegradable scaffolds in dorsal skinfold chambers of mice.

For tissue engineering, scaffolds should be biocompatible and promote neovascularization. Because little is known on those specific properties, we herein studied in vivo the host angiogenic and inflammatory response after implantation of commonly used scaffold materials. Porous poly(L-lactide-co-glycolide) (PLGA) and collagen-chitosan-hydroxyapatite hydrogel scaffolds were implanted into dorsal skinfold chambers of balb/c mice. Additional animals received cortical bone as an isogeneic, biological implant, while chambers of animals without implants served as controls. Angiogenesis and neovascularization as well as leukocyte-endothelial cell interaction and microvascular permeability were analyzed over 14 day using intravital fluorescence microscopy. PLGA scaffolds showed a slight increase in leukocyte recruitment compared to controls. This was associated with an elevation of microvascular permeability, which was comparable to that observed in isogeneic bone tissue. Of interest, PLGA induced a marked angiogenic response, revealing a density of newly formed capillaries almost similar to that observed in bone implants. Histology showed infiltration of macrophages, probably indicating resorption of the biomaterial. In contrast, hydrogel scaffolds induced a severe inflammation, as indicated by an approximately 15-fold increase of leukocyte-endothelial cell interaction and a marked elevation of microvascular permeability. This was associated by induction of apoptotic cell death within the surrounding tissue and a complete lack of ingrowth of newly formed microvessels. Histology confirmed adequate engraftment of PLGA and isogeneic bone but not hydrogel within the host tissue. PLGA scaffolds show a better biocompatibility than hydrogel scaffolds and promote vascular ingrowth, guaranteeing adequate engraftment within the host tissue.

Absorbable Implants↗
PubMed2005

Navigational maxillofacial surgery using virtual models.

Ablative tumor surgery and orbital and midface reconstruction, as much as orthognathic surgery, requires detailed planning using computed tomography (CT) or magnetic resonance imaging (MRI). These techniques also allow simulation of complex surgeries preoperatively. Proper reconstruction depends on reliable information to choose the correct type of grafts and to predict the outcome. This study evaluates the benefit and indications of computer-assisted surgery in the treatment of 107 patients who underwent craniomaxillofacial surgery. Based on a CT or MRI data set, an optical navigation system was used for preoperative planning, intraoperative navigation, and postoperative control. Surgery could be preoperatively planned and intraoperatively navigated. Preoperatively, it required that soft and hard tissues were measured using the mirrored data set of the unaffected side; the size and location of the graft were chosen virtually. Intraoperatively contours of transplanted tissues were navigated to the preoperatively simulated reconstructive result. Computer-assisted treatment was successfully completed in all 107 cases. Preoperatively outlined safety margins could be exactly controlled during tumor resection. Reconstruction was designed and performed precisely as virtually planned. Image-guided treatment improves preoperative planning by visualizing the individual anatomy, outlining the intended reconstructive outcome, and by objectifying the effect of adjuvant therapy. Intraoperative navigation makes tumor and reconstructive surgery more reliable by showing the safety margins, saving vital structures, and leading the reconstruction to preoperatively planned objectives.

Adolescent↗
PubMed2005

Five-year experience with the transoral endoscopically assisted treatment of displaced condylar mandible fractures.

BACKGROUND: From April of 1998 to May of 2003, the minimally invasive transoral approach for endoscopically assisted reduction and osteosynthesis of 62 displaced condylar mandible fractures was performed in 58 patients. METHODS: By means of limited transoral incision, the endoscopically assisted reduction and fixation of condylar fractures was performed using 30- and 45-degree angled endoscopes. Twenty-five fractures were condylar and 37 were subcondylar. The condylar neck of the proximal fragment was displaced medially in 17 fractures and laterally in 45 fractures. Four patients presented bilateral condylar mandible fractures. Using angled endoscopes, good visibility of the fracture site was obtained, which allowed for precise anatomical reduction in all patients. An angulated drill and screwdriver facilitated miniplate fixation by means of the transoral approach. The mean operating time was measured in the last 30 consecutive cases: 1 hour 5 minutes. RESULTS: Postoperatively, all patients showed quick recovery to preinjury occlusion. Normal temporomandibular joint function was noted 6 months after surgery in all patients. CONCLUSIONS: The transoral endoscopically assisted treatment using an angulated drill and screwdriver is the method of choice for surgical management of displaced condylar fractures, even in fractures with medial override. Facial nerve injury and visible scars are avoided by using the transoral approach.

Adult↗
PubMed2005

Sinus floor elevation via hydraulic detachment and elevation of the Schneiderian membrane.

OBJECTIVES: Minor sinus floor elevation is a method with relatively high predictability but is technically demanding. Improvement of the technique and increase in the predictability are desirable. MATERIAL AND METHODS: A clinical protocol for minor sinus floor elevation with SLA-ITI (large grit acid-etched implants with diameter of 4.8 mm) is described. Using trephine instead of spiral burrs enables the harvesting of autogenous grafts from the implant socket and guarantees a perfect implant socket. The latter is necessary for optimal implant anchoring and for the hydraulic seal between socket and the osteotome. The whole allows a hydraulic detachment of the Schneiderian membrane, where the blood cushion gradually detaches and elevates the membrane, preventing its contact with the graft. RESULTS: Eight patients were successfully treated with the method described above. No membrane perforation occurred and an uneventful healing was observed in all patients. All implants were loaded prosthodontically 3 months after the implantation. CONCLUSIONS: The clinical protocol presented provides high predictability in clinical outcome, together with extremely low morbidity and shortened surgery.

Adult↗
PubMed2005

[Augmentation of alveolar ridge defects: autologous bone transplant from the zygomatic alveolar crest--a new technique].

The insertion of dental implants with simultaneous loss of alveolar bone still represents a challenge. A traumatical tooth loss within the range of the front of the maxillary is frequently connected with a clear substance defect. The goal of a pre-implantologically treatment must be therefore the hard tissue reconstruction of the defect. Thus the implant camp is optimized and the prosthetical necessary implant position is guaranteed. In this case report the reconstruction of a vertical and horizontal bone loss with a transplant from the Crista zygomatico alveolaris is represented. The withdrawal of the bone transplant took place under indulgence of the vestibular membrane of the maxillary sinus by means of piezosurgery. After an appropriate healing time the single tooth gap was supplied with an ITI implant of the company Straumann (Freiburg, Germany).

Alveolar Bone Loss↗
PubMed2004

Comparative study of locking plates in mandibular reconstruction after ablative tumor surgery: THORP versus UniLOCK system.

PURPOSE: This retrospective study compared 2 types of rigid locking plates (THORP and UniLOCK; Stratec Medical, Oberdorf, Switzerland) in 107 patients undergoing reconstruction for bridging mandibular defects following ablative tumor surgery. PATIENTS AND METHODS: From January 1993 to December 2000, 107 patients were reconstructed following ablative tumor surgery with 57 THORP plates and 50 UniLOCK plates. Study follow-up ranged from 18 to 87 months (average, 32 months). Complications were categorized into delayed wound healing, infection, plate exposure, and plate fracture, taking into account the type and timing of reconstruction. RESULTS: Overall type and number of complications show no statistically significant differences between THORP and UniLOCK groups. Infection was the most frequent type of complication (THORP, 30; UniLOCK, 32). Others included delayed wound healing (THORP, 13; UniLOCK, 12), plate exposure (THORP, 8; UniLOCK, 7), and plate fracture (THORP, 5; UniLOCK, 1). Plates were removed in 22 THORP and 11 UniLOCK plates. The most frequent reason for plate removal in both groups was infection. Other reasons for plate removal include tumor recurrence, plate fracture, plate exposure, or a combination of reasons. CONCLUSIONS: THORP and UniLOCK plates do not present statistically significant differences in the parameters studied. Nevertheless, the UniLOCK group had slightly better results. Considering that the THORP system is much bulkier and its screws bigger, our results lead to the conclusion that bridging osteosynthesis with a 2.4 UniLOCK system is adequate for plate reconstruction of mandibular defects.

Adult↗
PubMed2003

Color duplex sonography for the monitoring of vascularized free bone flaps.

OBJECTIVE: When vascular complications are suspected after the microsurgical transfer of free buried fibular bone flaps without a skin island, revision surgery often proves to be unnecessary. We sought to determine the efficacy of color duplex sonography in the close observation of bone graft patency postoperatively. Study design Twelve free fibular bone flaps without a skin island were postoperatively monitored through color duplex sonography with a 7.5-MHz scanner. RESULTS: With color duplex sonography, the rate of perfusion in the vascular pedicle could be visualized in all 12 fibular flaps. In 3 patients, vascular complications and flap failure were suspected. However, because adequate perfusion of the vascular pedicle was observed immediately after surgery and in the daily follow-up examinations, revision surgery was not necessary. CONCLUSIONS: Color duplex sonography is not time-consuming; in fact, it is a reliable, noninvasive, and inexpensive method for the postoperative monitoring of free bone flaps.

Bone Transplantation↗
PubMed2003

Frontiers in maxillofacial endoscopic surgery.

The use of endoscopically assisted techniques allows limited incisions for the open reduction of condylar process fractures. Intraoperative control after fracture reduction in areas of limited exposure and visibility is possible. In addition, the risk of facial nerve damage and extensive visible scars can be reduced by using minimally invasive endoscopic techniques. Although the use of endoscopically associated techniques in maxillofacial surgery offers many options and advantages, indications for open treatment of maxillofacial trauma have not changed. The repair of severely dislocated and comminuted fractures of the facial skeleton and major reconstruction of craniomaxillofacial structures still require extended exposure with traditional intraoral and extraoral approaches.

Endoscopy↗
PubMed2003

Follow-up of condylar fractures of the mandible in 8 patients at 18 months after transoral endoscopic-assisted open treatment.

PURPOSE: The results of endoscopic-assisted transoral approach for open reduction and miniplate fixation of condylar mandible fractures were evaluated 18 months after surgery. PATIENTS AND METHODS: The transoral endoscopic-assisted treatment of condylar fractures was performed in 8 consecutive patients from April 1998 to December 1999 at the University Hospital Freiburg. Four of 8 condylar fractures were dislocated, and 6 of the 8 patients had additional mandibular fractures. RESULTS: Anatomic reduction was achieved in all patients without facial nerve damage. There were no signs of bony resorption and good temporomandibular joint function 18 months after surgery. In 4 patients, the transoral management of condylar fractures was facilitated by angulated drills and screw drivers. Transbuccal stab incisions were not needed in these 4 patients. In all 8 patients, visible scars were avoided. CONCLUSIONS: The endoscopic-assisted transoral approach proved to be a reliable surgical method for condylar fractures when dislocation with lateral override was present.

Adult↗
PubMed2003

Lateral upper arm free flap for primary reconstruction of pharyngeal defects in ablative oncological surgery. Report of six consecutive cases.

Free microvascular flaps are an established method for soft tissue reconstruction following ablative oncological surgery in the head and neck. Functional reconstructions of the hypopharynx and the pharyngoesophageal segment (PES) are of particular relevance, as they are highly demanding surgical procedures. So far, the radial forearm free flap (RFFF) and the free jejunal transfer have been the transplants predominantly used for this purpose. The lateral upper arm free flap (LUFF) presents an alternative method for the fasciocutaneous tissue transfer. We report on our experience with the LUFF in a 56-year-old male patient with a pT3pN0M0 squamous cell carcinoma of the hypopharynx. A pharyngocutaneous fistula developed 5 days after pharyngolaryngectomy with bilateral neck dissection. The fistula was localized between the pharyngeal constrictor muscle and the esophagus and was closed with an LUFF from the left arm. Excellent flap adaptation to the remaining pharyngeal mucosa was observed. Although the length of the vascular pedicle and the diameter of the vessels in the LUFF are smaller than those in the RFFF, neither pedicle length nor vessel diameter proved to be a problem. The LUFF can be recommended as a well-vascularized, relatively safe and reliable flap for reconstruction of tubular structures such as the hypopharynx and the PES after tumor ablation and as an alternative to the RFFF. The flexibility of the LUFF allows surgeons to reconstruct the anatomy of the lost soft tissues as adequately as possible.

Aged↗
PubMed2003

Characteristics of oral cancer in a central European population: defining the dentist's role.

BACKGROUND: The authors conducted a study to evaluate the effectiveness of dentists in the early detection, treatment and postoperative care of oral squamous cell carcinoma, or SCC, in a central European population. METHODS: This multicenter retrospective study was conducted under the auspices of DOSAK (a German, Austrian and Swiss cooperative group on tumors of the maxillofacial region). A questionnaire was used to evaluate the diagnostic, treatment and postoperative processes involved in managing the care of patients with oral SCC. A total of 3,894 questionnaires was sent to patients who had been diagnosed with and operated on for oral SCC at least six months previously; 1,761 questionnaires were returned. Another 1,652 additional questionnaires were sent to their oral surgeons; 1,543 were returned. RESULTS: The pT staging was pT2 (40.41 percent), pT1 (31.30 percent), pT4 (16.35 percent) and pT3 (11.90 percent). In 61.3 percent of the patients, there was no evidence of metastases. In 40 percent of the patients, the dentist treated the first symptoms, whereas the physician did so in 27 percent of the patients. A total of 72.5 percent of the dentists and 40.11 percent of the physicians identified oral SCC correctly. CONCLUSIONS: Dentists should participate actively in oral cancer patients' rehabilitation processes through regular clinical follow-up examinations and restoration of intraoral function. Clinical Implications. Dentists should conduct an oral cancer screening at each patient visit. Patients who are at risk should undergo more intense surveillance. Dentists should advise their patients to stop high-risk habits such as smoking and help them make choices for healthier lifestyles.

Aged↗
PubMed2002

Follow-up in patients with oral cancer.

PURPOSE: To provide standardized follow-up of patients who underwent oral cancer treatment, the German-Austrian-Swiss Cooperative Group on Tumors of the Maxillofacial Region (DOSAK) established a schedule of check-up examinations for a 5-year period. MATERIALS AND METHODS: On the basis of a questionnaire, we investigated oncologic follow-up in respect to early detection of recurrences, cost and outcome efficiencies, and physician and patient judgment in the development of impairments. RESULTS: Only 11% of all operated patients participated regularly in the follow-up program within the first 3 years. Ultrasound was the most effective imaging for the detection of recurrences. Swallowing, speaking, tongue mobility, and facial appearance were the most common problems. Troubles with swallowing were mainly induced by poorly fitted dentures, discontinuity of the mandible, osteomyelitis, and xerostomia. Outer appearance was mostly impaired by scars, missing facial muscle function, and edema. The problem of chronic pain remained unsolved. CONCLUSION: Due to the sequelae of treatment, this study shows the need for close medical and psychological follow-up.

Austria↗
PubMed2002

Navigation-guided resection of temporomandibular joint ankylosis promotes safety in skull base surgery.

PURPOSE: Computer-assisted surgery (CAS) has not been a routine part of craniomaxillofacial surgery to date. This report investigates the use of CAS to promote the safe removal of ankylosed temporomandibular joint bone in the skull base. PATIENTS AND METHODS: Out of a total pool of experience with 102 navigation-guided CAS procedures between January 1998 and December 2000, we report on 2 cases of navigation-aided resection of severe ankylosis of the mandibular condyle with a predetermined safety margin of the resection toward the middle cranial fossa, and identification of the foramen ovale. RESULT: The use of CAS with navigation resulted in the promotion of safe surgical excision of the ankylosed skull base tissue. CONCLUSIONS: We regard navigation-aided resection of an ankylosis fo the mandibular condyle as a valuable additional technique in this potentially complicated procedure.

Adult↗
PubMed2002

Quantification of the neurodegenerative impact on the visual system following sudden retrobulbar expanding lesions - an experimental model.

INTRODUCTION: Afferent disorders of the visual system are a potential consequence following orbital trauma. The aim of this study was to investigate the tolerance of neurons in the retinal ganglion cell layer to acute expanding retrobulbar lesions. MATERIAL AND METHODS: In 42 male albino rats, intraorbital haemorrhage was simulated by transconjunctival insertion of a retrobulbar micro-balloon (filling volume 0.2-0.5 ml, duration of lesion 60 or 90 min). Neurodegeneration in the retinal ganglion cell layer was investigated by measuring the mean total neuron number and the mean neuron size. RESULTS: Increased retrobulbar volumes of 0.3 ml for 60 min led to a decrease in a number of neurons by 14.5% and in size of the neurons by 1.7%. Prolongation of the trauma to 90 min resulted in a decrease in number of neurons by 48.3% and in reduction of size of neurons by 22.1%. In contrast, a retrobulbar filling volume of 0.5 ml for 60 min resulted in a decrease in number of neurons by 11.4% and in size of neurons by 6.7%. CONCLUSION: The duration of a retrobulbar lesion leading to subsequent retinal ischaemia seems to be more important for neuron survival than the exerted pressure (once it is greater than a critical point for producing retinal ischaemia). The results strengthen the need for emergency treatment in cases of retrobulbar haemorrhage.

Animals↗